As industrial emission standards tighten across the globe, sectors including waste incineration, metallurgical sintering, glass and ceramic kilns, biomass boilers, and chemical hazardous waste incineration are frequently confronted with the issue of excessive NOx and SO₂ in low-temperature flue gas. Traditional SCR and SNCR denitrification technologies require reaction temperatures above 300°C, making them ineffective for low-temperature flue gas from kilns and incinerators. They also suffer from catalyst poisoning and clogging, high replacement costs, and can only remove NOx without simultaneous SO₂ treatment.
The industrial ozone generator enables integrated flue gas desulfurization and denitrification through the strong oxidizing properties of ozone. It has become a popular low-temperature flue gas treatment solution for overseas EPC environmental projects and factory retrofits for ultra-low emissions. Centered on the ozone generator, this ozone oxidation system produces high-concentration ozone on-site to decompose NOx, SO₂, heavy metals and partial VOCs in flue gas, delivering simultaneous removal of multiple pollutants for industrial exhaust with fluctuating flow and low operating temperatures.
1. What is Ozone-Based Flue Gas Desulfurization and Denitrification?
Ozone (O₃) is a powerful oxidizing agent with a much higher oxidation potential than conventional chemicals used for desulfurization and denitrification, and it serves as the key reactant for NOx SO2 removal. An industrial ozone generator uses high-voltage discharge to ionize oxygen and produce high-concentration ozone. The ozone is injected evenly into the flue duct via specialized nozzles and fully mixed with low-temperature flue gas to trigger oxidation reactions.
Raw nitric oxide (NO) in flue gas is barely soluble in water and hard to capture by scrubbers, which is the biggest pain point of traditional denitrification technologies. Ozone rapidly oxidizes NO into soluble higher-order nitrogen oxides such as NO₂ and N₂O₅. While breaking down NOx, ozone also reacts with SO₂ in the flue gas and treats heavy metals and trace VOCs at the same time.
The oxidized flue gas then flows into an alkaline scrubber tower, where alkaline spray neutralizes and absorbs all acidic pollutants. This ozone flue gas treatment process operates stably at 80–200°C, completing both denitrification and desulfurization in one pass. It also offers auxiliary functions including mist elimination, dust reduction and decolorization, making it ideal for industrial exhaust projects where high-temperature reaction conditions are unavailable.
2. Full Working Process of Ozone Generators for Desulfurization & Denitrification
This industrial ozone oxidation flue gas treatment system runs in a fully automatic closed loop and supports 24-hour unattended continuous operation. The complete workflow is outlined below:
Gas Source Pre-treatment: PSA industrial oxygen generators supply oxygen feed. The oxygen passes through multi-stage filtration, deep drying and pressure stabilization to remove moisture and particulate impurities. This protects the ozone generator’s discharge chamber, extends equipment service life and stabilizes ozone output concentration.
Ozone Generation System: Purified oxygen enters the discharge chamber of the ozone generator. High-voltage ionization produces high-concentration ozone gas, the core unit of this low-temperature flue gas desulfurization and denitrification process.
Precision Dosing & Injection: Custom flue gas injection nozzles distribute ozone uniformly inside the duct and optimize flow field mixing. This ensures thorough contact between ozone and flue gas, prevents local ozone shortage or over-dosing, and improves NOx and SO₂ removal efficiency.
Low-Temperature Oxidation Reaction: Oxidation takes place rapidly between 80°C and 200°C. Insoluble NO converts into soluble high-valence nitrogen oxides, while SO₂, trace VOCs and heavy metals are oxidized. No extra flue gas heating is required, cutting substantial thermal energy costs.
Alkaline Scrubbing & Absorption: The oxidized high-valence pollutants are highly water-soluble. Alkaline spray in the scrubber fully neutralizes and absorbs these gaseous contaminants, transferring them into the liquid phase.
Treated Gas Discharge: After scrubbing and purification, NOx and SO₂ levels of the flue gas meet industrial emission standards worldwide to achieve ultra-low emissions.
Intelligent Automatic Control: Online monitors continuously collect flue gas flow, NOx concentration, SO₂ concentration and gas temperature data. The control system automatically adjusts ozone output from the ozone generator to match real-time demand, reducing energy consumption and operating costs.
3. Ozone Oxidation vs. Traditional SCR / SNCR Processes
Traditional SCR and SNCR denitrification have clear limitations for low-temperature kilns, waste incinerators and retrofits of old boilers. The key advantages of the ozone generator desulfurization and denitrification solution are listed below:
No high-temperature requirement: Oxidation starts at 80°C instead of 300°C+, making it a preferred option for low-temperature flue gas treatment. It works directly for low-temperature exhaust from kilns and incinerators.
No catalyst required: The ozone oxidation process does not rely on catalysts. There is no catalyst poisoning, clogging or recurring high replacement cost, greatly lowering long-term maintenance expenses.
Integrated multi-pollutant control: One ozone system removes NOx and SO₂ simultaneously, along with partial VOCs and odors. A single unit handles multiple pollutants and simplifies the overall environmental process.
Minimal retrofit work: No modification to the boiler main body and no large high-temperature reaction tower are needed. The compact footprint makes the solution well-suited for ultra-low emission upgrades on existing plants.
No secondary pollution risks: Ozone quickly decomposes back into oxygen after reactions with no residual substances. It avoids ammonia slip commonly seen in SCR/SNCR and does not generate large volumes of solid waste, easing solid waste disposal burdens.
Fully automatic continuous operation: The industrial ozone oxidation system runs reliably 24/7 and tolerates large fluctuations in flue gas flow and pollutant concentrations to maintain stable compliant emissions.
4. Core Advantages of Black Lion Industrial Ozone Generators
Black Lion industrial ozone generators are engineered specifically for flue gas desulfurization and denitrification and built to withstand harsh industrial flue gas conditions:
High-performance ozone generation cell: Premium dielectric discharge tubes and stable high-voltage discharge technology deliver high ozone concentration with low decomposition rate and strong oxidation capacity to sustain reliable NOx SO2 removal performance.
Water-cooled temperature control system: The built-in water cooling structure removes heat generated during discharge and suppresses ozone thermal breakdown. This allows the ozone generator to run non-stop all year round for long-term industrial operations.
Intelligent variable-frequency control system: Linked to upstream flue gas online analyzers, it adjusts ozone output power automatically based on real-time pollutant readings. Ozone is dosed on demand to avoid waste of power and raw materials and reduce energy consumption for the whole low-temperature flue gas treatment system.
Oxygen-fed configuration: Can work together with PSA oxygen generators. Oxygen feed delivers higher ozone concentration and better oxidation efficiency than air-fed ozone generators, which is the premium setup for large-scale flue gas desulfurization and denitrification projects.
Anti-corrosion and explosion-proof industrial design: Piping and chambers use corrosion-resistant materials to cope with flue gas carrying high dust, high humidity and corrosive components. The robust equipment can handle tough operating conditions from waste incineration, metallurgy and kiln applications.
5. Main Industries & Application Scenarios
The ozone generator for flue gas desulfurization and denitrification works across a wide range of operating conditions. Typical use cases include:
Low-temperature flue gas treatment for waste incineration plants and hazardous waste incinerators
NOx and SO₂ treatment for biomass, coal-fired and gas-fired boiler exhaust
Flue gas desulfurization and denitrification projects for steel sintering machines and blast furnaces in metallurgy
Ultra-low emission retrofits for glass kilns, ceramic kilns and refractory kilns
Coordinated pollutant removal for chemical tail gas, pharmaceutical incineration and coating incineration waste gas
Low-temperature flue gas treatment upgrades for thermal power plants and district heating boiler stations
6. Conclusion
Ultra-low emission regulations for industrial flue gas keep tightening around the world. Conventional high-temperature denitrification technologies such as SCR and SNCR struggle to meet treatment demands for low-temperature kilns, incinerators and boiler exhaust.
The ozone oxidation flue gas desulfurization and denitrification technology with ozone generators stands out with benefits including low-temperature adaptability, combined NOx and SO₂ removal, catalyst-free operation, low maintenance cost and simple on-site retrofitting. It has gained wider adoption among international EPC environmental engineering projects.
Black Lion supplies complete packages including industrial ozone generators, supporting PSA oxygen systems, intelligent control modules and flue gas ozone injection assemblies. We design customized low-temperature flue gas treatment solutions according to flue gas parameters from different industries, helping facilities consistently meet NOx and SO₂ emission requirements and satisfy global environmental compliance standards.